With an increase in the population of advanced ages in recent years, patients with senile dementia increase in number, posing a serious problem medically and socially. Although various antidementia drugs have been investigated and developed in view of the situation, no compounds have been provided with satisfactory efficacy. It has been strongly desired to develop medicaments for treating the disease.
An object of the present invention is to provide novel oxindole derivatives which are very useful as medicaments for treating senile dementia, i.e., as cerebral function improving agents and cerebral metabolism activators or anoxic brain damage protectives.